Phishing defence and basic account hygiene.
The biggest risk on Nexus is a lookalike address, not the market itself. A stack of small habits keeps you safe.
Copy addresses from a signed source, never type them, and check against the captcha every session, because a saved bookmark can point at an address that has rotated out. If a login ever asks for your recovery phrase, close the tab.
A fresh username, a unique generated password in a local manager, the recovery phrase on paper, short sessions, and small on-market balances. Money on a market is money exposed to whatever happens to the market, so withdraw what you are not about to spend.